194 Mr. C Mcresclikowsky on SvilLvpUora. 



il. Monoplacatae. 



A. I'vrenoplioreoo {CymheVa, flomphovvma, Rhoicoapheniu, Aiio- 



mvcotwis, L'lebisso/iia, Aaciculii dicephaU). 

 Ji. Catemiliiceie {Cattnida). 



C. 8elliii)hovL';u (SeUap/iora). 



D. Coccoiieide;e or lletLroidea>, s. em. (Cocconcis, Microneis). 



III. Archaideae {Auricula, Aviphoropsis, Amphiprora, Epithcmia^ 

 ^fdurvticllu), 



28th September, 1901. 



EXPLANATION OF PLATE IV. 



I'if/. 1. Sellaphora picpula {Kz.),'Mer. Valve. ?«., median part of the 

 single clu'omatopbore; /?;-., its four lateral prolongations resting 

 on the connecting-zones; a, the margin of the latter turned up 

 on the surface of the valve ; Ip., libroplasts. Fresh water, 

 California. ^. 



Fif/. 2. Ditto. Girdle-face. ;?/., central plasma ; »/?., median part of the 

 plate seen in projection ; /;/•., the lateral prolongations of the 

 latter, f". 



Fit/. 3. Ditto. Valve; a typical specimen. Ip., m., and ;>/•., see fig. 1. 



IL'OO 



Fit/. 4. Ditto. Valve of a small individual. --. 



Fiff. 5. Ditto. Valve, after Grunow (Arct. Diat. pi. ii. fig. 53). ^-J?. 



Fi(/. G. Sc'lluphora L'urs(;otvii, 3Ier. Valve, very typical. ?«., median 



part of the chromatophore, with the two eheoplasts ; pr., its 



four lateral prolongations seen in projection. Marine, Cali- 



fornia. i^. 

 Fit/. 7. Ditto. Girdle-face of the same individual in a slightly ohlique 



position. J/?., median part ; pr., prolongations of the chroma- 



toi^hore. l^^i'. 

 Fit/. 8. Ditto. Another girdle-face, pi., central plasma ; nc, nucleus. 



1200 

 1 ■ 



Fir/. 9. Ditto. Valve, i^. 



Fit/. 10. Ditto. Valve; the smallest individual observed. ~. 



Fit/. 11. Diagram of a chromatophore-plate of a St'lfaj>/inra \y\th unfolded 

 margins, m., median jiart resting on the surface of the valve ; 

 pr., the four prolongations resting on the connecting-zone. 



Fit/. 12. Diagram representing a transverse section of a frustulo of ScUa- 

 phora. m., median part of the chromalophore resting on the 

 dorsal valve ; 2'^') prolongations resting on the connecting- 

 zones. 



Fitj. 13. SiUajihtna elli/itiia, Mer. A typical valve. Marine, Cali- 



[■ ■ 1 'JOO 



fornia. - . 



